# Gemini 3.8 Flash vs Grok 4.5

> Gemini 3.8 Flash is the stronger model overall, scoring 61.8 to 55.0 on the Noometry Index.

- Canonical page: https://noometry.com/compare/gemini-3-8-flash-vs-grok-4-5
- Last updated: 2026-10-10
- Shared benchmarks: 45

## Summary

- They share 45 benchmarks with published results for both. Gemini 3.8 Flash scores higher in 9 categories and Grok 4.5 in 1 category; 10 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Gemini 3.8 Flash leads 76.9 to 56.1.
- The biggest single-benchmark swing is WeirdML: 84.8% for Gemini 3.8 Flash and 46.4% for Grok 4.5.
- Gemini 3.8 Flash is cheaper at $0.75 / $3.75 per million input/output tokens, against $2 / $6 for Grok 4.5.
- Gemini 3.8 Flash accepts more context: 1.05M tokens versus 500K.

## Snapshot

| | Gemini 3.8 Flash | Grok 4.5 |
|---|---|---|
| Provider | Google | xAI |
| Noometry Index | 61.8 | 55.0 |
| Rank | 11 | 25 |
| Context | 1.05M | 500K |
| Input $/M | $0.75 | $2 |
| Output $/M | $3.75 | $6 |
| Weights | Proprietary | Proprietary |

## Coding

- Gemini 3.8 Flash: 59.2 (#15)
- Grok 4.5: 52.2 (#35)

| Benchmark | Gemini 3.8 Flash | Grok 4.5 |
|---|---|---|
| DeepSWE | 73.8% | 53.8% |
| FrontierCode | 41.2% | 42.4% |
| LMArena WebDev | 1584 | 1553 |
| SciCode | 56.6% | 54.1% |
| WeirdML | 84.8% | 46.4% |
| LMArena Coding | 1510 | 1474 |
| ALE-Bench | 1,270 | 1,309 |
| CursorBench | 39.6% | — |
| FrontierSWE | 19.6% | — |

## Agentic & Tool Use

- Gemini 3.8 Flash: 41.8 (#21)
- Grok 4.5: 44.4 (#17)

| Benchmark | Gemini 3.8 Flash | Grok 4.5 |
|---|---|---|
| APEX-Agents | 64.3% | 56.2% |
| GDP.pdf | 23.4% | 14% |
| Vending-Bench 2 | 5,094 | 3,887 |
| Remote Labor Index | 5.8% | — |
| τ²-bench Banking | — | 47.9% |
| PostTrainBench | — | 23.4% |
| GBAEval | — | 65.4% |
| LMArena Search | — | 1213 |

## Reasoning

- Gemini 3.8 Flash: 76.9 (#5)
- Grok 4.5: 56.1 (#25)

| Benchmark | Gemini 3.8 Flash | Grok 4.5 |
|---|---|---|
| ARC-AGI-2 | 89.2% | 52.6% |
| NYT Connections (extended) | 97.4% | 79.9% |
| ARC-AGI-1 | 98.5% | 87.2% |
| CritPt | 18.3% | 15.4% |
| Chess Puzzles | 61% | 36% |
| LMArena Hard Prompts | 1508 | 1462 |
| DTBench | 95.7% | 96.5% |
| LMCA | 52.9% | 45.2% |
| Surface Evolver Bench | 76.9% | 74.4% |
| Epoch Capabilities Index | 156.71 | 153.92 |
| SimpleBench | — | 70% |
| Kagi LLM Benchmark | — | 83.5% |
| Mystery Game Puzzles | 47% | — |

## Math

- Gemini 3.8 Flash: 65.3 (#28)
- Grok 4.5: 60.9 (#35)

| Benchmark | Gemini 3.8 Flash | Grok 4.5 |
|---|---|---|
| FrontierMath (Tiers 1-3) | 68.4% | 57.2% |
| FrontierMath Tier 4 | 22% | 24.4% |
| OTIS Mock AIME 2024-2025 | 98.9% | 97.8% |
| ProofBench | 48% | 31% |
| LMArena Math | 1528 | 1459 |

## Knowledge

- Gemini 3.8 Flash: 74.8 (#2)
- Grok 4.5: 62.3 (#24)

| Benchmark | Gemini 3.8 Flash | Grok 4.5 |
|---|---|---|
| GPQA Diamond | 95.4% | 93.4% |
| SimpleQA Verified | 69.7% | 48.3% |
| LMArena Expert | 1524 | 1466 |
| Humanity's Last Exam | 44.5% | — |

## Multimodal

- Gemini 3.8 Flash: 40.7 (#45)
- Grok 4.5: 37.6 (#72)

| Benchmark | Gemini 3.8 Flash | Grok 4.5 |
|---|---|---|
| LMArena Vision | 1314 | 1288 |
| Blueprint-Bench 2 | 38.6% | 27.3% |
| Furniture Assembly | 31.7% | 22.5% |
| LMArena Document | — | 1452 |

## Multilingual

- Gemini 3.8 Flash: 58.0 (#5)
- Grok 4.5: 54.4 (#42)

| Benchmark | Gemini 3.8 Flash | Grok 4.5 |
|---|---|---|
| LMArena Non-English | 1491 | 1440 |
| LMArena Chinese | 1554 | 1496 |
| LMArena French | 1498 | 1456 |
| LMArena German | 1493 | 1446 |
| LMArena Japanese | 1502 | 1428 |
| LMArena Korean | 1459 | 1404 |
| LMArena Russian | 1515 | 1448 |
| LMArena Spanish | 1485 | 1450 |

## Instruction Following

- Gemini 3.8 Flash: 78.0 (#13)
- Grok 4.5: 76.0 (#48)

| Benchmark | Gemini 3.8 Flash | Grok 4.5 |
|---|---|---|
| LMArena Instruction Following | 1490 | 1446 |

## Long Context

- Gemini 3.8 Flash: 46.3 (#24)
- Grok 4.5: 44.8 (#56)

| Benchmark | Gemini 3.8 Flash | Grok 4.5 |
|---|---|---|
| LMArena Longer Query | 1508 | 1463 |

## Writing & Preference

- Gemini 3.8 Flash: 72.2 (#15)
- Grok 4.5: 65.8 (#42)

| Benchmark | Gemini 3.8 Flash | Grok 4.5 |
|---|---|---|
| LMArena Text | 1499 | 1448 |
| LMArena Creative Writing | 1492 | 1442 |
| EQ-Bench Creative Writing | 1748 | 1579 |
| LMArena Multi-Turn | 1501 | 1456 |

## FAQ

### Is Gemini 3.8 Flash better than Grok 4.5?

Gemini 3.8 Flash is the stronger model overall, scoring 61.8 to 55.0 on the Noometry Index.

### Which is cheaper, Gemini 3.8 Flash or Grok 4.5?

Gemini 3.8 Flash is cheaper. It lists at $0.75 per million input tokens and $3.75 per million output tokens; Grok 4.5 lists at $2 and $6.

### Is Gemini 3.8 Flash or Grok 4.5 better for coding?

Gemini 3.8 Flash scores higher on coding benchmarks: 59.2 versus 52.2 in the Noometry coding category.

### Which has the bigger context window?

Gemini 3.8 Flash does, with 1.05M tokens against 500K.

### How many benchmarks do Gemini 3.8 Flash and Grok 4.5 share?

45 benchmarks have published results for both models. Gemini 3.8 Flash has 50 scored results on Noometry and Grok 4.5 has 52.